Talks between striking fuel tanker drivers and their employers are set to resume today.
The drivers' four-day strike is set to end at 6am on Tuesday, and talks are being planned to avert a second four-day strike, which is set to begin at 6am this Friday.
The current strike is reported to have led to an increase of 25% in demand for fuel as motorists panic-buy, with around 600 of the UK's 8700 petrol stations running out of fuel so far.
The worst-hit areas are Cardiff, Cornwall, London and the West Midlands.
However, the union representing the workers, Unite, says there is ground for optimism. Assistant-general secretary of Unite, Len McCluskey, said: 'We're hopeful. We'll be working hard to try and conclude a satisfactory resolution to the dispute.'
Bernie Holloway, a director at Hoyer UK, one of the haulage firms affected, said: 'I don't think we should kid ourselves - there's a lot of work to be done.'
The two sides are due to meet at a secret location later on Monday morning.
The haulage companies said the unions rejected a pay offer that would take the drivers' average salary to 41,500 by January 2009.
However, Unite says the offer would have increased salaries from just under 32,000 to 36,000.
The union also says it is in dispute with Shell, because it is the oil giant with dictates the structure and price of the tanker contracts.